Field of the Invention
The present invention relates to the field of tools and machines for injection molding of plastic and other thermoplastic materials.
Discussion of Related Art
Injection molding devices having one or more rotating center parts are known from the prior art. These are used for the efficient manufacture of multi-component plastic parts by injection molding. At least one rotatable mold center part (center block), which is fixed to a holding device and is rotatably arranged about an axis of rotation, is arranged between two mold halves, the mold halves being movable against one another along tie bars in a first direction. The rotatable mold center part has at least two parallel side surfaces, along which it interacts with the two mold halves for the formation of the cavities. In certain embodiments, the rotatable mold center part can interact at least on one side with a further rotatable mold center part. Coordinating means effect that the rotatable mold center part remains positioned centrally between the two mold halves during opening and closing, and thus collisions are avoided. Several holding devices for the rotatable middle part are known from the prior art.
EP1035959 and EP1155802 were published in 1999 by the same applicant, and both relate to a holding device for a rotatable center part (mold, mold half, mold carrier). The holding device has a lower and an upper cross member which are guided along the tie bars of an injection molding machine. Each cross member of the holding device has a rotatable holding means, which serves for releasable clamping the mold, mold half or the mold carrier therebetween.
EP1725386 of the same applicant was published in 2005, and relates to a method and an injection molding device with more than one rotatable center part. This makes it possible to manufacture parts in two outer parting planes and to assemble these in a further parting plane in a further manufacturing step. In the figures, different embodiments of holding devices for the rotatable center parts are illustrated.
WO2011/107395 by the same applicant was published in 2011 and describes a holding device with a modular structure, which can be flexibly adapted to different injection molding machines. Different types of holding are described.
EP1119449 by the company Krauss Maffei was first published in 2001 and shows a two-plate horizontal injection molding machine. This has a holding device for a rotatable center part mounted on the machine bed. The holding device in the invention is fully detached from the tie bars and has no operative connection with these. All occurring forces are transmitted via the machine bed.
An object of the invention is to further improve the injection molding devices known from the prior art with respect to their efficiency.